The California Citizens Redistricting Commission is withholding final signature on a contract with its newly hired federal voting rights lawyers after staff members discovered undisclosed political activities.

Gibson, Dunn & Crutcher failed to inform the commission during mid-March interviews that the firm is a registered federal lobbyist with a federal political action committee, or that several of the attorneys assigned to the redistricting project team have contributed individually to presidential candidates.

“The fact that the firm is a registered federal lobbying firm and that it gave more than $2,000 to campaigns should have been disclosed,” said Commissioner Angelo Ancheta, a Democrat and San Francisco law professor. “I have made it very clear that if it was intentional or willful nondisclosure, then I would recommend terminating our contract.”

Gibson Dunn has registered lobbyists among its 1,000 attorneys, but none of the lawyers assigned to the redistricting team is a lobbyist.

“In terms of disclosure, we gave the commission what it asked for and now they are asking for more, which we have provided,” she said.

The brouhaha is another in a series of early skirmishes over whether the commission’s choice of consultants reveals a partisan bias that will taint California’s independent redistricting experiment.

The panel, composed of 14 people from outside the traditional political world, is also under heavy time pressure, and missteps early in the process could jeopardize its mandate to draw 177 new congressional, legislative and board of equalization districts by Aug. 15.

The commission awarded Gibson, Dunn & Crutcher a $150,000 contract in mid-March after a partisan deadlocked vote that ultimately led the sole remaining competitor — Nielsen, Merksamer, Parrinello, Gross & Leoni — to withdraw its bid. Most of the Republican commissioners preferred Nielsen, while the Democrats and nonpartisan members wanted Gibson Dunn.

The act bars the drawing of political boundaries that dilute minorities’ political clout. If the U.S. Department of Justice deems the new maps in violation, the issue could wind up in court.

Nielsen Merksamer drew commissioners’ objections largely on the grounds that it is a registered California lobbying firm whose attorneys represent counties and have served in the past as counsel to the national and California Republican Party. The firm also disclosed that it represents public agencies seeking exemption from the Voting Rights Act provisions.

But in the days after the bid award, redistricting staff learned that Gibson Dunn is a registered federal lobbying firm with a political action committee that has contributed thousands of dollars to candidates of both parties.

In 2009, for example, its political action committee contributed $2,500 each to U.S. Sen. John McCain, R-Ariz., and the Democratic Senatorial Campaign Committee, according to the online federal lobby registry.

None of the Gibson Dunn lawyers named to head up the California redistricting project, Democrat George Brown and Republican Dan Kolkey, is a registered federal or state lobbyist but both have contributed money to candidates.

Brown donated $4,300 in 2008 to the campaign of then-presidential candidate Barack Obama, according to OpenSecrets.com. Kolkey contributed, in the same year, $2,300 to McCain’s presidential campaign.

Under the law that created the redistricting panel, elected officials, lobbyists and individuals who contributed $2,000 or more to any congressional, state or local candidate are ineligible to serve as commissioners. Contributions to presidential candidates are not included.

But the applicable provisions do not apply to hired consultants, Ancheta said. The commission feared overly tight restrictions would further limit an already small pool of redistricting and voting rights experts.

“This is where we gave ourselves some flexibility,” Ancheta said. “For me, being a lobbyist doesn’t disqualify a consultant. I want to look at the client list.”

It is an inexcusable lapse, said Tony Quinn, a veteran GOP redistricting expert who has said the commission’s choices clearly reveal a bias toward the left.

He has also panned the commission’s choice of Q2 Data, an Oakland-based mapmaking technical consulting firm whose minority business partner, UC-Berkeley Professor Bruce Cain, was hired to help California Democrats redistrict in the 1980s.

“I watched you conflict out the Nielsen Merksamer firm as a lobbying firm while you were busy hiring Gibson Dunn, another lobbying firm, in order to employ the services of left-wing activist attorney George Brown,” Quinn wrote the commissioners.

Piatt, the Gibson Dunn spokeswoman, rejected Quinn’s characterization of Brown and described the redistricting team as bipartisan.

Brown represented Latino voters in lawsuits challenging under the California Voting Rights Act the method of elections in Modesto and Madera Unified School District. He also represents a number of corporate clients, Piatt said.

The other lead attorney, Kolkey, was an elected judge in 2002, served on a Republican Party central committee and was counsel to former Gov. Pete Wilson in 1992 litigation involving California redistricting.

He also wrote or helped write Propositions 11 and 20, the voter-approved measures that created the Citizens Redistricting Commission.